Measuring Peroxide Value Research Articles

Antioxidant activity of rosemary (<i>Rosmarinus officinalis L.</i>) extracts on natural olive and sesame oils.

The antioxidant activities of chloroform and methanol extracts of rosemary ( Rosmarinus officinalis L .) were tested in natural olive and sesame oils stored at 55 °C, by measuring peroxide values after regular intervals. The concentrations of extracts and citric acid had been used as 1% and 2%. The extracts (except for 12,16 and 20 days in storage of olive oil) exhibited high antioxidant activity compared with control sample in olive and sesame oil. Antioxidant effects of both extracts and citric acid levels in olive oil showed statistically different after from 4 days of storage (p < 0.01 ). The most effective concentration on sesame oil during storage had 2% chloroform extract. Furthermore, especially 2% concentrations of both solvent extracts of rosemary shown significantly antioxidative activity in compared with citric acid on sesame oil.

On the Role of Squalene in Olive Oil Stability

The role of squalene in olive oil stability was studied for various concentrations and experimental conditions. No effect was found in induction periods of olive oil at elevated temperatures using the Rancimat apparatus. Samples were then stored at 40 and 62 degrees C in the dark, and the extent of oxidation was followed by periodic measurements of peroxide value and conjugated dienes. A concentration dependent moderate antioxidant activity was evidenced which was stronger in the case of olive oil compared to that found for sunflower oil and lard. In the presence of alpha-tocopherol (100 mg/kg) and caffeic acid (10 mg/kg) the contribution of squalene (7000 mg/kg) was not significant. No radical scavenging activity was observed using DPPH(*) in 2-propanol. The weak antioxidant activity of squalene in olive oil may be explained by competitive oxidation of the different lipids present which leads to a reduction of the oxidation rate. Squalene plays a rather confined role in olive oil stability even at low temperatures.

Antioxidant synergy of α‐tocopherol and phospholipids

AbstractThe prevention of oxidation of a refined sardine oil by α‐tocopherol at 0.04%, by several phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), and cardiolipin (CL)] at 0.5%, as well as by combinations of α‐tocopherol with each phospholipid, was investigated. The evolution of the oxidation process during 1 mon at 40±2°C was followed by a series of methods, measuring peroxide value (PV), diene, triene, and polyene index, and absorbance at 430 nm, while α‐tocopherol and phospholipid content were being monitoried. Among these indices, PV was found to be the most adequate to follow the process. PC was the most effective individual antioxidant as shown by the PV values obtained at the end of the storage period, which were 54.0, 83.4, 87.9, and 97.7 meq O2/kg for PC, CL, PE, and α‐tocopherol, respectively. The highest synergistic effect was obtained with a mixture of α‐tocopherol and PE, and the second and third best by mixtures made with PC and CL, respectively. The corresponding PV values recorded at the end of the period were 27.0, 35.0, and 58.0 meq O2/kg. The high degree of synergy between PE and tocopherol is probably due to the occurrence of a simultaneous antioxidant mechanism involving Maillard compounds.

Principal component analysis of measured quantities during degradation of hydroperoxides in oxidized vegetable oils.

Decomposition of hydroperoxides in sunflower oil under strictly oxygen-free conditions was followed by measuring peroxide values against time, absorbance values at 232 and 268 nm, para-anisidine values, and by quantitative analyses of volatile products using various additives. The results were arranged in a matrix form and subjected to principal component analysis. Three principal components explained 89-97% of the total variance in the data. The measured quantities and the effect of additives were closely related. Characteristic plots showed similarities among the measured quantities (loading plots) and among the additives (score plots). Initial decomposition rate of hydroperoxides and the amount of volatile products formed were similar to each other. The outliers, the absorbance values, were similar to each other but carried independent information from the other quantities. Para-anisidine value (PAV) was a unique parameter. Since PAV behaved differently during the course of hydroperoxide degradation, it served as a kinetic indicator. Most additives were similar in their effects on the mentioned quantities, but two outliers were also observed. Rotation of the principal component axes did not change the dominant patterns observed. The investigations clearly showed which variables were worth measuring to evaluate different additives.

ANTIOXIDANT ACTIVITY OF CITRUS HYSTRIX PEEL EXTRACT IN RBD PALM OLEEN DURING FRYING OF FISH CRACKERS

ABSTRACTThe Citrus hystrix peel extract (2,000 ppm) and butylated hydroxytoulene(BHT) (200 ppm) were added to the frying oil. The antioxidant activities were determined during deep fat frying of fish crackers for 4 consecutive days. Each frying period was for 5 h and intermittent frying at 180C with half an hour interval was carried out. The antioxidant activities were determined by measuring peroxide value (PV), p‐anisidine value (AnV), totox value, iodine value (IV), percent free fatty acids, color and viscosity of the oil. Results indicated that the ethanol extract of the citrus peel exhibited antioxidant properties and therefore has a potential as one of the new sources of natural antioxidants.

Actividad antioxidante de compuestos aislados del residuo no-volátil del aceite esencial de naranja.

There has been a growing interest in the food industry and in preventive medicine to search for «natural antioxidants». Therefore the objetive of this study was to evaluate the antioxidant activity of the non-volatile residue of essential orange oil in the oxidation of unrefined and freshly extracted olive oil. Essential orange oil was distilled to obtain a non-volatile residue and fracctionated on a Silica Gel 60 column. The antioxidant activity was determined by measuring peroxide value obtained after heating olive oil at 70 °C for 48 h. Six compounds were isolated and purified, four of these had antioxidant activity, α-tocopherol and three methoxylated flavones were identified using spectroscopic methods. This study confirmed that non-volatile fractions of essential orange oil contain natural antioxidants diferent from α-tocopherol.

Antioxidant properties of myricetin and quercetin in oil and emulsions

AbstractThe effect of quercetin and myricetin on the stability of sunflower oil and oil‐in‐water emulsions was studied by storage experiments monitored by measurement of peroxide values, conjugated dienes, and headspace volatile analysis. Myricetin showed strong antioxidant activity in oils stored at 60 or 30°C and in oil‐in‐water emulsions stored at 30°C, whether tocopherols or citric acid were present or not; however, quercetin showed similar antioxidant activity in stripped sunflower oil but no activity in oils that contained tocopherols and citric acid. This showed that myricetin is effective owing to strong radical scavenging and metal‐chelating properties, whereas quercetin has weaker radical scavenging activity, although it is also active by metal‐chelation. The effects of copper and iron salts on the antioxidant activity of myricetin and quercetin were studied in sunflower oil and oil‐in‐water emulsions. Quercetin and myricetin enhanced the prooxidant effect of cupric chloride in oil‐in‐water emulsions (pH 7.4), but this effect was not observed with cupric stearate. The addition of myricetin to emulsions that contained ferric chloride at pH 5.4 also produced a strong prooxidant effect, and small prooxidant effects of flavonols were also detected in the presence of cupric chloride under these conditions. However, myricetin and quercetin reduced the prooxidant effect of ferric palmitate in oils. Myricetin also showed a strong antioxidant effect in oil that contained cupric stearate, although quercetin had no significant effect on the oxidative stability of this system. It therefore appears that flavonols may exert a prooxidant effect in the presence of metal salts, but the nature of the metal salt is important in determining whether a prooxidant effect occurs.

Identification and function of antioxidants from oat groats and hulls

AbstractAntioxidant components of methanolic extracts of groats and hulls from Ogle oats were identified and quantified by using gas chromatography‐mass spectrometry (GC‐MS) and gas chromatography after N,O‐bis(trimethylsilyl)acetamide derivatization. Ferulic, p‐coumaric, vanillic, p‐hydroxybenzoic, 4‐hydroxyphenylacetic acids and vanillin and catechol were quantified in groat and hull extracts. Additionally, caffeic acid in groat extracts, and o‐coumaric, sinapic and slaicylic acids in hull extracts were quantified. Extracts from groats and hulls at levels of 0.05, 0.1, 0.2, and 0.3% w/w, based on total phenolic content, were added to soybean oil, and their antioxidant effectiveness was compared with that of 0.02% w/w tertiary butylhydroquinone (TBHQ) and a control (no additives) at 60°C in the dark by measuring peroxide values. Antioxidant activities of both extract sources increased with increased concentration. During 20 d of storage, the groat extract (0.3%) was not significantly different from TBHQ after day 16, and hull extracts (0.2 and 0.3%) were not significantly different from TBHQ on day 20. Oils containing pure phenolics at the same concentrations measured in the groat and hull extracts oxidized more quickly than did oils containing the extracts.

Studies on the Improvement of Antioxidant Effect of Tocopherols. XXVI.

An evaluation was made on antioxidative and synergistic effects of several emulsifiers on cookie by storage test at 40°C for 12 months after baking. Emulsifiers were added to cookie dough at 0.5%, and effects were evaluated by sensory test and measuring peroxide value of lipid fraction of cookie to compare inhibition of increase of peroxide. Lecithin showed a strong antioxidant effect on cookie. Sorbitan monostearate and sucrose fatty acid ester (hydroxyl value : 362) showed a less effect than that of lecithin. In the case of emulsifiers in combination with a mixed tocopherols concentrate, sorbitan monostearate showed a synergistic effect, and propylene glycol monostearate showed an additive effect. Synergistic effect of lecithin, however, could not be observed obviously because of their strong antioxidant effect.

Action of β-Carotene on Purified Rapeseed Oil During Light Storage

The purified triacylglycerol fraction of rapeseed oil was used as a food lipid model to study the effects of β-carotene and γ-tocopherol on its oxidative stability in light. The triacylglycerol fraction of rapeseed oil was oxidized under fluorescent light at 25°C. Oxidation was followed by measuring peroxide value and the consumption of antioxidants. Under air, β-carotene (20 μg/g) was a pro-oxidant, whereas γ-tocopherol (20 μg/g) was an effective inhibitor of lipid oxidation. When both β-carotene (20 μg/g) and γ-tocopherol (20 to 50 μ/g) were present together, the oxidation was inhibited more effectively than by γ-tocopherol alone. Our findings suggest that there is potential antioxidant benefit in combining β-carotene and γ-tocopherol in food systems.

Composition and antioxidant activity of essential oils from Oregano plants grown wild in Greece

In this study, four samples of essential oils obtained from plant species with a wide distribution in Greece and economic importance for the world-wide spice market and also carvacrol and thymol were tested for their possible antioxidant activity. The four plant species wereOriganum vulgare subsp.hirtum, O. onites, Coridothymus capitatus andSatureja thymbra. The essential oils were chemically characterised by gas chromatography-ion trap detection. All the essential oils examined and also carvacrol and thymol were found to have antioxidant activity when tested on TLC plates and by measuring peroxide values of lard stored at 35° C. The results indicate that the antioxidant effect may be related to the presence of carvacrol and thymol in essential oils.

STORAGE STABILITY AND ACCELERATED SHELF‐LIFE TESTING OF MARGARINE SAMPLES

ABSTRACTThe extent of oxidative and storage stability of margarine samples were determined by measuring peroxide values (PV) and Accelerated Shelf‐Life Testing (ASLT). Two margarine samples, A and B, which were packaged with parchment and Acrylonitrile butadiene styrene (ABS), respectively, were studied to predict their storage stabilities. Samples were stored at 4 and 14C in the dark as being typical of long term storage (LTS) conditions to study the deteriorative parameters of PV and free fatty acid (FFA). Induction times estimated from ASLT results were 9.18, 5.32 and 2.65 h for Margarine (A), and 8.92, 5.12 and 2.6 h for Margarine (B) at 100, 110 and 120C, respectively. During long term storage at 4 and 14C the shelf‐life, based on peroxide formation, values were determined as 145 and 108 for Margarine (A), and 134 and 96 days for Margarine (B) at these temperature, respectively. Only a slight increase in the FFA content was observed on either sample. The main goal of the study was to test the methodology utilized rather than to compare packaging materials.

Rapid and Simple Coulometric Measurements of Peroxide Value in Edible Oils and Fats

Abstract A rapid coulometric method was developed for the measurement of peroxide value In edible oils and fats. The sample size and reagents volumes In this method are considerably less than those in the American Oil Chemists' Society method. Iodine produced by the reaction of the Iodide Ion and peroxide In the sample Is electrochemlcally reduced at the carbon-felt electrode more rapidly than it is with lodometric titration. The present method Is successfully applied to the measurements of edible oils and fats, and the coulometric results obtained are consistent with those obtained by iodometry.

Measurement of Peroxide Value in Edible Oils and Fats, and in Foods by Rapid Coulometry

Rapid coulometry was developed for the rapid and sensitive measurement of peroxide value (POV) of edible oils and fats, and foods by using a carbon felt electrode with ferrocyanide ion as a mediator. The reaction mechanism is as follows: 1) iodine is formed by the reaction of iodide ion and peroxide in the sample, 2) the reaction of iodine and ferrocyanide ion produces ferricyanide ion, and 3) ferricyanide ion is electrochemically reduced within 25 sec at the working electrode, which is maintained at -0.4V vs. the counter electrode.It was possible to conduct 25 repeated injections of 5μl of sample solution. A linear relationship between charge and concentration of iodine was observed over the range of 5×10-5×10-2M which corresponded to a POV range of 1.3-446. The analytical results obtained by rapid coulometry were in good agreement with those by iodometry.

Lipid peroxidation of liposome induced by glucosone.

Lipid peroxidation of liposome made of egg lecithin was induced by glucosone (D-arabino-hexos-2-ulose), a secondary product of Maillard reaction or glycation of protein. Lipid peroxidation was assessed with measurement of TBARS (thiobarbituric acid reacting substances), POV (peroxide value), and HPLC measurement of MDA (malondialdehyde). EDTA and DTPA (diethylenetriamine-pentaacetic acid) inhibited the lipid peroxidation assessed by each method described above, indicating involvement of metal ions. The observed reduction of Fe3+ to Fe2+ by glucosone might be a critical step of the lipid peroxidation. Our findings suggest a possible role of lipid peroxidation of low-density lipoproteins (LDL) induced by glucosone in atherosis caused by diabetes mellitus.

Determination Methods of Lipid Hydroperoxides

It has been passed many years since much interests were paid on lipid hydroperoxidation in some research fields such as foods, medicines, cosmetics and their related industries. During these decades, there are many reports on development and modification of lipid hydroperoxides determination methods, which is able to perform precise and reproducible analysis with a very small sample size. Those methods are contributing for not only evaluation of toxicity or effect of lipid hydroperoxides on living bodies but also quality control of oil and fat products.However, some methods used with halogen-containing solvents, for example the official and tentative methods for peroxide value measurement have to make further modification based on looking for alternative solvent since environmental pollution by halogen compounds is proceeding rapidly.In the present review, some popular or novel methods which are classified into titrimetric, colorimetric, enzymatic and instrumental methods are introduced and characterized.

Effect of maillard reaction volatile products on lipid oxidation

AbstractMaillard reaction volatile compounds (MRV), prepared by heating a glucose‐glycine solution, were tested as antioxidants in soybean oil (SBO) thermoxidation. The volatiles were transferred into the oil by stripping with a stream of Nitrogen and substituting the atmosphere above the oil with air containing MRV. Standard accelerated oxidation was performed by heating the SBO. Peroxide value measurement and headspace gas Chromatographic analysis were carried out on all the samples. The MRV antioxidant activity was evaluated by determining the effect of the induction period and the kinetic rate constant of peroxide and oxidation volatiles formation. The MRV showed a significant antioxidant activity. The effectiveness was variable depending on MRV transfer method to the oil, and the Maillard reaction extent was related to the browning level of glucose/glycine solution. It was found that the maximum effect of MRV prolonged about three times the induction period and reduced the kinetic rate constant by half in relation to the control sample. MRV affects oxidative stability of soybean oil by lengthening the induction period as well as by decreasing the rate of oxidation at the propagation state and reducing the formation of hexanal.

Effects of quenching mechanisms of carotenoids on the photosensitized oxidation of soybean oil

AbstractThe effects of 0, 1.0 × 10”−5, 2.5 × 10−5, and 5.0 × 10−5 M β‐apo‐8'‐carotenal, β‐carotene, and canthaxanthin on the photooxidation of soybean oil in methylene chloride containing 3.3 × 10−9 M chlorophyll b were studied by measuring peroxide values and conjugated diene content. β‐Apo‐8'‐carotenal, β‐carotene, and canthaxanthin contain 10,11, and 13 conjugated double bonds, respectively. The peroxide values and conjugated diene contents of oils containing the carotenoids were significantly lower (P&lt;0.05) than those of control oil containing no carotenoid. As the number of conjugated double bonds of the carotenoids increased, the peroxide values of soybean oils decreased significantly (P&lt;0.05). The quenching mechanisms and kinetics of the carotenoids in the photosensitized oxidation of soybean oil were studied by measuring peroxide values. The steady‐state kinetics study showed that carotenoids quenched singlet oxygen to reduce chlorophyll‐sensitized photooxidation of soybean oil. The singlet‐oxygen quenching rate constants ofβ‐ apo‐8'‐carotenal, β‐carotene, and canthaxanthin were 3.06 × 109, 4.60 × 109, and 1.12 × 1010 M−1sec−1, respectively.

Oxidation of rapeseed oil: Effect of metal traces

Traces of heavy metals in edible oils are known to have an effect on the rate of oil oxidation. In this investigation we studied the effect of trace metals by excluding instead of adding them. Three supports were used to fix trace metals: grafted cellulose, cationic resin and absorbent resin. Cationic resin and grafted cellulose allowed copper (Cu) and iron (Fe) to be fixed. The measurement of peroxide value and variation of linolenic acid with temperature indicate good oxidative stability of oil processed on cellulose and cationic resin. These results confirm the effect of metals, particularly Fe and Cu, on oil oxidation.

Increased levels of lipid peroxides in aged rat brain as revealed by direct assay of peroxide values

Lipid peroxide concentrations in brain tissues of young and aged rats were determined by a direct method for measuring peroxide values. Three different brain regions were analyzed for lipid peroxides. The peroxide levels increased in all three regions of aged as compared to those of young rats, while lipid peroxides in plasma appeared to be stable along with age. Lipid peroxides in cerebrum and cerebellum increased 1.6–2.0 times in aged brains compared with young ones, and about 3-fold in the brain stem. Increased levels of lipid peroxides in aged brains seem not merely due to increased pools of precursor polyene fatty acids, but rather due to altered protection systems for lipid peroxidase formation.